Dual connecting and disconnecting apparatus

ABSTRACT

A cylinder tube of a second hydraulic cylinder is provided separate from a first piston of a first hydraulic cylinder and integrally fixed to an input shaft. Friction members of a first clutch and friction members of a second clutch are prevented from moving in a first direction by a snap ring attached to a connecting drum. The friction members of the first clutch are friction engaged by the first piston and the friction members of the second clutch are friction engaged by a second piston.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a connecting and disconnecting apparatus of aclutch or a brake or the like. More particularly, the invention relatesto a dual connecting and disconnecting apparatus in which a pair ofconnecting and disconnecting apparatuses are arranged in series in theaxial direction.

2. Description of the Related Art

A vehicular automatic transmission is known which uses a plurality ofplanetary gearsets, clutches, and brakes. The automatic transmissiondisclosed in Japanese Patent Laid-Open Publication No. 2001-304355,which is one such example, is provided with a dual connecting anddisconnecting apparatus having (i) a first hydraulic cylinder in which apiston is moved in a first direction which is parallel with an axis ofthe dual connecting and disconnecting apparatus by supplying hydraulicfluid into a pressure chamber, (ii) a second hydraulic cylinder which isintegrally provided on a common support member (i.e., an input shaft 2)and which is concentric with the first hydraulic cylinder in a positionadjacent in the first direction to the first hydraulic cylinder, and inwhich a piston is moved in the first direction by supplying hydraulicfluid into a pressure chamber, (iii) a cylindrical connecting drumprovided on a side wall portion of a cylinder tube of the firsthydraulic cylinder integrally mounted to the support member, theconnecting drum being centered around the axis and protruding out in thefirst direction; (iv) a first friction engaging device (i.e., a clutch)positioned farther to the first direction side than the second hydrauliccylinder, the first friction engaging device having (a) a plurality offriction members provided on the connecting drum, this connecting drumbeing rotatable around the axis with respect to a first connectingmember (i.e., a sun gear), the plurality of friction members beingnon-rotatable with respect to the connecting drum, and (b) a pluralityof friction members provided on the first connecting member, theplurality of friction members being non-rotatable with respect to thefirst connecting member, the first friction engaging device connectingthe support member with the first connecting member via the connectingdrum by moving the piston of the first hydraulic cylinder in the firstdirection and engaging the plurality of friction members of theconnecting drum with the plurality of friction members of the firstconnecting member; and (v) a second friction engaging device (i.e., aclutch) positioned farther to the first direction side than the secondhydraulic cylinder and adjacent in the axial direction to the firstfriction engaging device, the second friction engaging device having (a)a plurality of friction members provided on the connecting drum, thisconnecting drum being rotatable around the axis with respect to a secondconnecting member (i.e., a sun gear), the plurality of friction membersbeing non-rotatable with respect to the connecting drum, and (b) aplurality of friction members provided on the second connecting member,the plurality of friction members being non-rotatable with respect tothe second connecting member, the second friction engaging deviceconnecting the support member with the second connecting member via theconnecting drum by moving the piston of the second hydraulic cylinder inthe first direction and engaging the plurality of friction members ofthe connecting drum with the plurality of friction members of the secondconnecting member. The piston of the first hydraulic cylinder alsoserves as a cylinder tube of the second hydraulic cylinder. That pistonis engaged with the connecting drum so as to be non-rotatable withrespect thereto. The friction members of the second friction engagingdevice are fitted to the piston so as to be non-rotatable with respectthereto and held in position by a stopper member (i.e., a snap ring)attached to the piston.

In this kind of dual connecting and disconnecting apparatus, however,because the second hydraulic cylinder and the second friction engagingdevice within the cylinder type of the first cylinder are able to movein the axial diction, the sliding resistance and the like of these partsresults in the hydraulic pressure in one of the pressure chambersaffecting the hydraulic pressure in the other pressure chamber. As aresult, it is difficult to finely control both the engaging torque ofthe first friction engaging device and the engaging torque of the secondfriction engaging device at the same time, thereby restricting the useof the two friction engaging devices.

Furthermore, because the friction members of the second frictionengaging device are fitted to the piston of the first hydraulic cylinderso as to be non-rotatable with respect thereto, a cylindrical drum andspline teeth or the like must be provided on the piston in addition tothe connecting drum provided on the cylinder tube, which results in acomplex piston shape and high manufacturing costs. Also, because torqueis transmitted via the piston of the first hydraulic cylinder when thesecond friction engaging device is engaged, the operating resistance ofthe piston of the first hydraulic cylinder changes depending on whetherthe second friction engaging device is engaged or disengaged, whichmakes transitional control of the engaging torque when engaging anddisengaging the first friction engaging device difficult, for example.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the invention toprovide a dual connecting and disconnecting apparatus in which a firstfriction engaging device and a second friction engaging device aremounted to a connecting drum integrally provided on a cylinder tube of afirst hydraulic cylinder, and in which engaging torque of both of thefriction engaging devices can be finely controlled at the same time witha high degree of accuracy, and in which the piston shape is simplifiedsuch that the entire apparatus can be made easily and inexpensively.

In order to achieve the foregoing object, a dual connecting anddisconnecting apparatus according to a first aspect of the invention,which has (a) a first hydraulic cylinder in which a piston is moved in afirst direction which is substantially parallel with an axis of the dualconnecting and disconnecting apparatus by supplying hydraulic fluid intoa pressure chamber, (b) a second hydraulic cylinder which is integrallyprovided on a common support member and which is concentric with thefirst hydraulic cylinder in a position adjacent in the first directionto the first hydraulic cylinder, and in which a piston is moved in thefirst direction by supplying hydraulic fluid into a pressure chamber;(c) a cylindrical connecting drum provided on a side wall portion of acylinder tube of the first hydraulic cylinder integrally mounted to thesupport member, the connecting drum being centered around the axis andextending out in the first direction; (d) a first friction engagingdevice positioned farther to the first direction side than the secondhydraulic cylinder, the first friction engaging device comprising (i) afriction member provided on the connecting drum, this connecting drumbeing rotatable around the axis with respect to a first connectingmember, the friction member being non-rotatable with respect to theconnecting drum, and (ii) a friction member provided on the firstconnecting member, the friction member being non-rotatable with respectto the first connecting member, the first friction engaging deviceconnecting the support member with the first connecting member via theconnecting drum by moving the piston of the first hydraulic cylinder inthe first direction and engaging the friction member of the connectingdrum with the friction member of the first connecting member; and (e) asecond friction engaging device positioned farther to the firstdirection side than the second hydraulic cylinder and adjacent in theaxial direction to the first friction engaging device, the secondfriction engaging device comprising (i) a friction member provided onthe connecting drum, this connecting drum being rotatable around theaxis with respect to a second connecting member, the friction memberbeing non-rotatable with respect to the connecting drum, and (ii) afriction member provided on the second connecting member, the frictionmember being non-rotatable with respect to the second connecting member,the second friction engaging device connecting the support member withthe second connecting member via the connecting drum by moving thepiston of the second hydraulic cylinder in the first direction andengaging the friction member of the connecting drum with the frictionmember of the second connecting member, is characterized in that (f) acylinder tube of the second hydraulic cylinder is provided separatelyfrom the piston of the first hydraulic cylinder, and is fixed integrallyto the support member, and (g) the friction members of the firstfriction engaging device and the friction members of the second frictionengaging device are fitted into the connecting drum from an end portionthereof on the first direction side from the direction opposite thefirst direction, and are prevented from moving in the first direction bya stopper member integrally attached to the connecting drum.

According to this dual connecting and disconnecting apparatus, thecylinder tube of the second hydraulic cylinder is provided separatelyfrom the piston of the first hydraulic cylinder and fixed integrally tothe support member. In addition, the friction member of the firstfriction engaging device and the friction member of the second frictionengaging device are prevented from moving in the first direction by thestopper member attached to the connecting drum. As a result, thefriction member of the first friction engaging device and the frictionmember of the second friction engaging device become friction engagedwhen pressed against by the piston. Therefore, the first hydrauliccylinder and the second hydraulic cylinder can engage and disengage thefirst friction engaging device and the second friction engaging deviceseparately. As a result, the engaging torque of the first frictionengaging device and the engaging torque of the second friction engagingdevice can be finely controlled at the same time with a high degree ofaccuracy, which increases the degree of freedom of the modes in whichthe pair of friction engaging devices can be used. For example, the pairof friction engaging devices can be used for clutch-to-clutch shifting,in which one device is disengaged while the other is engaged.

Further, the dual connecting and disconnecting apparatus may also besuch that (a) among the first friction engaging device and the secondfriction engaging device, the friction member on the connecting drumside of the one friction engaging device arranged on the side oppositethe first direction side in the axial direction is mounted to theconnecting drum so as to be non-rotatable with respect thereto; and (b)the piston of the hydraulic cylinder that engages the friction member ofthe other friction engaging member positioned on the first directionside extends through a notch formed in the friction member of the onefriction engaging device and abuts against the friction member of theother friction engaging device.

According to this construction, the friction member on the side oppositethe first direction side in the axial direction, i.e., on the connectingdrum side of the one friction engaging member arranged adjacent to thesecond hydraulic cylinder is mounted directly to the connecting drum soas to be non-rotatable with respect thereto. Further, the piston of thehydraulic cylinder that engages the friction member of the otherfriction engaging device positioned on the first direction side extendsthrough the notch provided in the friction member of the one frictionengaging device and abuts against the friction member of the otherfriction engaging device. Therefore, there is no need to provide acylindrical drum and spline teeth or the like on the piston, as there iswhen fitting the friction member to the piston of the first hydrauliccylinder so as to be non-rotatable with respect thereto, as is doneconventionally. As a result, the shape of the piston is simplified,making the entire apparatus easier and inexpensive to make. Furthermore,there is no fear that the operating resistance of the piston of thehydraulic cylinder that engages the other friction engaging device willchange depending on whether the one friction engaging device is engagedor disengaged so transitional control and the like of the engagingtorque during engagement and disengagement of the other frictionengaging device is able to be performed with a high degree of accuracyregardless of whether the one friction engaging device is engaged ordisengaged.

Also, the dual connecting and disconnecting apparatus may also be suchthat (a) among the first friction engaging device and the secondfriction engaging device, the friction member of the one frictionengaging device arranged on the side opposite the first direction sidein the axial direction is prevented from the first direction side, frommoving in the first direction by a spacer fitted to the connecting drumso as to be non-rotatable with respect thereto; and (b) the frictionmember on the connecting drum side of the other friction engaging devicepositioned on the first direction side is fitted to the spacer so as tobe non-rotatable with respect thereto, and is prevented, along with thespacer, from moving in the first direction by the stopper member.

According to this construction, the friction member of the one frictionengaging device on the side opposite the first direction side in theaxial direction, i.e., the friction member of the one friction engagingdevice arranged adjacent to the second hydraulic cylinder, is preventedfrom moving in the first direction by the stopper member via the spacer.As a result, the length dimension of the apparatus is able to be reducedin the axial direction compared to when separate stopper members areprovided for the friction member of the one friction engaging device andthe friction member the other friction engaging device. Also, a snapring is typically used as the stopper member. However, because the snapring must be compressed in the radial direction when it is fit into anannular groove for assembly in the connecting drum (or expanded in theradial direction after it is fit into the annular groove), it isnecessary to increase the radial dimension of the snap ring so that itis greater than the radial dimension necessary for engagement with thefriction member, but only by the amount that the snap ring is compressed(or expanded) (i.e., by only the amount of the snap ring that will fitinto the annular groove in the connecting drum) in order to avoidinterference with the piston that engages the other friction engagingdevice. When the spacer is used, however, its radial dimension onlyneeds to be equal to the dimension required to engage the frictionmember and no greater, so the radial dimension of the spacer can bedecreased compared to the radial dimension of the snap ring.

In addition, an annular flange bent at a substantially right angle awayfrom the connecting drum so as to be substantially parallel with thefriction member of the one friction engaging apparatus may be integrallyprovided on an end of the spacer.

According to this construction, because the flange is provided on thespacer that prevents the friction member of the one friction engagingdevice from moving in the first direction, pressure from the piston isable to be distributed evenly over a wide area of the friction member.As a result, localized heat generation and uneven friction areinhibited, and performance in terms of durability and engaging force andthe like of the friction engaging device is improved. Furthermore, thepressure plate (i.e., friction member) that contacts the spacer can bemade thinner or even eliminated entirely, thereby reducing the cost andenabling the overall length to be reduced. Also, by providing theflange, the rigidity of the spacer itself is increased so the work offorming the splines on the spacer which fit with the friction member ofthe other friction engaging device and the connecting drum so that thespacer is non-rotatable with respect to both of these, is made easier,thereby enabling manufacturing costs to be reduced.

Further, the dual connecting and disconnecting apparatus may beconstructed such that the spacer is prevented from moving in thedirection opposite the first direction by an abutting portion providedintegrally with the connecting drum so as to allow fitting of thefriction member of the one friction engaging device, and is held inposition between the abutting portion and the stopper member.

Accordingly, when the one friction engaging device is disengaged, it ispossible to prevent a deterioration in power transmission efficiency andfuel efficiency caused by the spacer moving in the direction oppositethe first direction when the friction engaging device is disengaged andcausing the friction members to slip engage, resulting in dragging lossand heat buildup which can burn the friction members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a skeleton view of a vehicular automatic transmission towhich the invention has been applied, and FIG. 1B is a table showingengagement/disengagement combinations of friction elements for achievingeach speed;

FIG. 2 is an alignment graph for the exemplary embodiment shown in FIG.1A and FIG. 1B;

FIG. 3 is a cross-sectional view showing in detail clutch C1 and C2portions of the vehicular automatic transmission shown in FIG. 1A;

FIG. 4 is a view showing the relationship between the friction member ona connecting drum side of the clutch C2 shown in FIG. 3 and a piston ofa first hydraulic cylinder;

FIG. 5A is a localized cross-sectional view of the exemplary embodimentshown in FIG. 3, which shows in detail how the friction members areengaged with the connecting drum of the second clutch C2, and FIG. 5B isa cross-sectional view showing in detail how the connecting drum, aspacer, and the friction members in the first clutch C1 are engaged witheach other;

FIG. 6 is a cross-sectional view which corresponds to FIG. 3, whichshows another exemplary embodiment of the invention; and

FIG. 7 is a cross-sectional view which also corresponds to FIG. 3, whichshows yet another exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A dual connecting and disconnecting apparatus according to the inventionis preferably applied to a power transmitting apparatus of a vehicle,such as a planetary gear type automatic transmission or aforward-reverse switching apparatus that switches between a plurality ofspeeds and forward and reverse according to an operating state of aclutch and a brake which serve as a friction engaging device, forexample. Further, the dual connecting and disconnecting apparatus of theinvention can also be applied to a power transmitting apparatus otherthan a power transmitting apparatus used in a vehicle.

A hydraulic cylinder and friction engaging device according to theinvention are cylindrical in shape and centered around an elongatedsupport member, for example. A connecting drum is integrally connectedto an outer cylinder of a cylinder tube of the first hydraulic cylinderso as to be continuous therefrom. A first friction engaging device and asecond friction engaging device are housed on the inner peripheral sideof the connecting drum. Various other aspects are possible, however,such as providing the connecting drum so that it is continuous from aninner cylinder of the first hydraulic cylinder and arranging thefriction engaging device on the outer peripheral side of that connectingdrum, or arranging the hydraulic cylinder and the friction engagingdevice on the inside of the connecting drum using a cylindrical supportmember, or employing a device having a disk-shaped piston having thecenter portion serve as the second hydraulic cylinder.

In both the first friction engaging device and the second frictionengaging device, it is preferable to use multiple-disc clutches andbrakes in which at least two friction members are provided on each oftwo members that are rotatable relative to each other. Alternatively,however, it is also possible to employ a single-disc friction engagingdevice in which there is only one friction member provided on each ofthe two members.

The transmission of power between the support member and the firstconnecting member or the second connecting member may be such that poweris either transmitted from the support member to the first or secondconnecting member or from the first or second connecting member to thesupport member, or the direction of power transmission may even bechanged according to a specific condition. Also, the support member,first connecting member, and second connecting member may all berotatable around the axis. Alternatively, any one of those members maybe fixed to a housing or the like so as to be unable to rotate aroundthe axis. Also, the first connecting member and the second connectingmember may be so that they are not connected to each other and arerotatable with respect to each other, or they may be connected to eachother so as to rotate together.

It is preferable that the second friction engaging device be onefriction engaging device and the first friction engaging device beanother friction engaging device, but the reverse is also possible.

Also, the friction members on the connecting drum side of the onefriction engaging device are directly mounted to the connecting drum soas to be non-rotatable with respect thereto. Alternatively, similar tothe related art, a piston for engaging the other friction engagingdevice may be engaged with the connecting drum so as to be non-rotatablewith respect thereto, and the friction members of the one frictionengaging device may be mounted to the piston so as to be bothnon-rotatable, yet movable in the axial direction, with respect thereto,as long as movement of the friction members in a first direction isprohibited by at least one stopper member mounted to the connectingdrum.

Further, the friction members of the other friction engaging device maybe fitted to a spacer so as to be non-rotatable with respect thereto,and the friction members of the one friction engaging device may beprohibited from moving in the first direction by the spacer. Also, thefriction members on the connecting drum side of both the one and theother friction engaging device may be fitted to the connecting drum soas to be non-rotatable with respect thereto, and movement of thosefriction members in the first direction may be prohibited by a separatestopper member for each of the friction engaging devices.

Because the spacer is fitted to both the friction members of the otherfriction engaging device and the connecting drum so as to benon-rotatable with respect both of these, splines are provided on thecylindrical inner and outer peripheral surfaces of the spacer, forexample. However, it is also possible to form the spacer by bending ordrawing it with a press into a wavy shape in which the dimension of thediameter changes cyclically around the periphery. The waves of can beused to function as splines, and can be made both easily andinexpensively. By also forming the connecting drum into a wavy shape bysimilar press work, splines can also be formed on the connecting drumboth easily and inexpensively.

Also, an abutting portion may be provided. In this case, a step may beformed by making the dimensions of the portion of the connecting drumwhere the friction members of the one friction engaging device arefitted different from those of the portion of the connecting drum wherethe spacer is fitted, for example, and this step may be used as theabutting portion. That is, when the connecting drum is positioned on theouter peripheral side, by making the diameter of the connecting drumlarger at the portion where the spacer is fitted than at the portionwhere the friction members of the one friction engaging device arefitted, the friction members of the one friction engaging device areable to be fitted to the connecting drum, while the spacer abuts againstthe step (i.e., the abutting portion) between the small diameter portionand the large diameter portion, thus preventing the spacer from movingin the direction opposite the first direction. In a case in which thefriction members of the one friction engaging device are fitted to theconnecting drum so as to be non-rotatable with respect thereto via apiston for engaging the other friction engaging device, as well, a stepmay be provided by making the dimension of the diameter of the portionwhere the piston is fitted different from the dimension of the diameterof the portion where the spacer is fitted. The abutting portion may be aprotrusion that protrudes to either the inner peripheral side or theouter peripheral side and engages the spacer. For example, movement ofthe spacer may also be prevented by fixing an abutting portion which isa separate member, such as a bolt which screws in the radial direction,to the connecting drum. In this way, various aspects are possible.

Hereinafter, a first exemplary embodiment of the invention will bedescribed in detail with reference to the drawings.

FIG. 1A is a skeleton view of a vehicular automatic transmission 10 towhich the invention has been applied. FIG. 1B is a table showingengagement/disengagement combinations of friction elements for achievinga plurality of speeds. The vehicular automatic transmission 10 is atransversely mounted transmission for use in an FF (i.e., front engine,front-wheel drive) vehicle or the like, and includes a firsttransmitting portion 14 and a second transmitting portion 20 on a singleaxis. The first transmitting portion 14 has a double pinion type firstplanetary gearset 12 as its main component, while the secondtransmitting portion 20 has a single pinion type second planetarygearset 16 and a double pinion type third planetary gearset 18 as itsmain components. The vehicular automatic transmission 10 takes therotation from the input shaft 22, changes it, and outputs the changedrotation to an output gear 24. The input shaft 22 corresponds to aninput member such as a turbine shaft of a torque converter driven by adriving source for running an engine or the like. The output gear 24corresponds to an output member and drives left and right driven wheelsvia a differential gear unit The vehicular automatic transmission 10 issubstantially symmetrical with respect to its center line or axis. InFIG. 1A, the half below the center line has been omitted.

The first planetary gearset 12, which largely makes up the firsttransmitting portion 14, includes three rotating elements, which are asun gear S1, a carrier CA1, and a ring gear R1. The sun gear S1 isconnected to, and driven by, the input shaft 22, while the carrier CA1is fixed via a third brake B3 to a case 26 which does not rotate. Thering gear R1 functions as an intermediate output member, outputtingpower while rotating at a slower speed than the input shaft 22. Further,the second planetary gearset 16 and the third planetary gearset 18,which together largely make up the second transmitting portion 20, arecoupled together at four portions which serve as four rotating elementsRM1 to RM4. More specifically, a sun gear S3 of the third planetarygearset 18 serves as the first rotating element RM1; a ring gear R2 ofthe second planetary gearset 16 and a ring gear R3 of the thirdplanetary gearset 18 are coupled together and serve as the secondrotating element RM2; a carrier CA2 of the second planetary gearset 16and a carrier CA3 of the third planetary gearset 18 are coupled togetherand serve as the third rotating element RM3; and a sun gear S2 of thesecond planetary gearset 16 serves as the fourth rotating element RM4.The second planetary gearset 16 and the third planetary gearset 18together form a Ravigneaux type planetary gear train, in which thecarriers CA2 and CA3, as well as the ring gears R2 and R3, are shared ascommon members, and the pinion gear of the second planetary gearset 16also serves as the second pinion gear of the third planetary gearset 18.

The first rotating element RM1 (i.e., the sun gear S3) can beselectively prevented from rotating by coupling it to the case 26 by afirst brake B1. The second rotating element RM2 (i.e., the ring gears R2and R3) may be selectively coupled to the input shaft 22 by a firstclutch C1 and selectively prevented from rotating by coupling it to thecase 26 with a second brake B2. The fourth rotating element RM4 (i.e.,the sun gear S2) can be selectively coupled to the input shaft 22 via asecond clutch C2. The first rotating element RM1 (i.e., the sun gear S2)is integrally connected to the ring gear R1 of the first planetarygearset 12, which serves as the intermediate output member. The thirdrotating element RM3 (i.e., the carriers CA2 and CA3) is integrallyconnected to the output gear 24 and outputs rotation thereto. The firstbrake B1, the second brake B2, third brake B3, first clutch C1, andsecond clutch C2 together serve as a multiple-disc hydraulic frictionengaging device in which they are all frictionally engaged by ahydraulic cylinder. Along with the second brake B2, a one-way clutch F,which allows forward rotation of the second rotating element RM2 (i.e.,rotation in the same direction as that of the input shaft 22) whilepreventing reverse rotation, is also provided between the secondrotating element RM2 and the case 26.

FIG. 2 is an alignment graph illustrating, using straight lines, therotational speed of each of the rotating elements of the firsttransmitting portion 14 and the second transmitting portion 20. Thelower horizontal line in the drawing denotes a rotational speed of “0”and the upper horizontal line in the drawing denotes a rotational speedof “1.0”, i.e., a rotational speed the same as that of the input shaft22. Further, the vertical lines corresponding to the first transmittingportion 14 denote, in order from left to right, the sun gear S1, thering gear R1, and the carrier CA1, with the intervals between thoselines set according to a gear ratio ρ1 (= the number of teeth on the sungear/the number of teeth on the ring gear) of the first planetarygearset 12. Similarly, the four vertical lines corresponding to thesecond transmitting portion 20 denote, in order from left to right, thefirst rotating element RM1 (i.e., the sun gear S3), the second rotatingelement RM2 (i.e., the ring gears R2 and R3), the third rotating elementRM3 (i.e., the carriers CA2 and CA3), and the fourth rotating elementRM4 (i.e., the sun gear S2), with the intervals therebetween setaccording to a gear ratio ρ2 of the second planetary gearset 16 and agear ratio ρ3 of the third planetary gearset 18.

As is evident from the alignment graph, when the second clutch C2 andthe second brake B2 are engaged, such that the fourth rotating elementRM4 rotates integrally with the input shaft 22 and the second rotatingelement RM2 is kept from rotating, the third rotating element RM3coupled to the output gear 24 rotates at a rotational speed denoted by“1st” and a first speed “1st”, which has the largest gear ratio, isachieved. When the second clutch C2 and the first brake B1 are engaged,such that the fourth rotating element RM4 rotates integrally with theinput shaft 22 and the first rotating element RM1 is kept from rotating,the third rotating element RM3 rotates at a rotational speed denoted by“2nd” and a second speed “2nd”, which has a gear ratio smaller than thatof the first speed “1st”, is achieved. When the second clutch C2 and thethird brake B3 are engaged, such that the fourth rotating element RM4rotates integrally with the input shaft 22 and the first rotatingelement RM1 rotates via the first transmitting portion 14 at a slowerspeed than the input shaft 22, the third rotating element RM3 rotates ata rotational speed denoted by “3rd” and a third speed “3rd”, which has agear ratio smaller than that of the second speed “2nd”, is achieved.When the first clutch C1 and the second clutch C2 are engaged, such thatthe second transmitting portion 20 rotates integrally with the inputshaft 22, the third rotating element RM3 rotates at a rotational speeddenoted by “4th”, i.e., the third rotating element RM3 is rotated at thesame speed as the input shaft 22, and a fourth speed “4th”, which has agear ratio smaller than that of the third speed “3rd”, is achieved. Thisfourth speed “4th” has a gear ratio of 1:1. When the first clutch C1 andthe third brake B3 are engaged, such that the second rotating elementRM2 rotates integrally with the input shaft 22 and the first rotatingelement RM1 rotates via the first transmitting portion 14 at a slowerspeed than the input shaft 22, the third rotating element RM3 rotates ata rotational speed denoted by “5th” and a fifth speed “5th”, which has agear ratio smaller than that of the fourth speed “4th”, is achieved.When the first clutch C1 and the first brake B1 are engaged, such thatthe second rotating element RM2 rotates integrally with the input shaft22 and the first rotating element RM1 is kept from rotating, the thirdrotating element RM3 rotates at a rotational speed denoted by “6th” anda sixth speed “6th”, which has a gear ratio smaller than that of thefifth speed “5th”, is achieved. Further, when the second brake B2 andthe third brake B3 are engaged, such that the second rotating elementRM2 is kept from rotating and the first rotating element RM1 rotates viathe first transmitting portion 14 at a slower speed than the input shaft22, the third rotating element RM3 rotates in reverse at rotationalspeed denoted by “Rev” and a reverse speed “Rev” is achieved.

The table in FIG. 1B shows the relationships between each of the speedsand the operating states of the first clutch C1, the second clutch C2,the first brake B1, the second brake B2, and the third brake B3. Thesingle circle denotes engagement and the double circle denotesengagement only with engine braking. Because the one-way clutch F isprovided along with the second brake B2 used to achieve the first speed“1st”, it is not always necessary to engage the second brake B2 whentaking off (i.e., when accelerating). Also, the gear ratio for eachspeed is set appropriately according to the gear ratio ρ1 of the firstplanetary gearset 12, the gear ratio ρ2 of the second planetary gearset16, and the gear ratio ρ3 of the third planetary gearset 18.

FIG. 3 is a cross-sectional view showing in detail the upper half, fromthe centerline or axis 0, of a dual connecting and disconnectingapparatus 30 which enables and interrupts the transmission of powerbetween the input shaft 22 which serves as the support member, thesecond rotating element RM2 which serves as the first connecting member,and the fourth rotating element RM4 which serves as the secondconnecting member. The dual connecting and disconnecting apparatus 30 isalso provided with a first hydraulic cylinder 32 which frictionallyengages the first clutch C1, and a second hydraulic cylinder 34 whichfrictionally engages the second clutch C2. The first hydraulic cylinder32 and second hydraulic cylinder 34 are both cylindrical and areintegrally attached to the input shaft 22, centered therearound on thesame axis so that they rotate together with the input shaft 22 aroundthe axis 0.

The first hydraulic cylinder 32 is provided with a cylinder tube 36 anda piston 38. The cylinder tube 36, which is formed in a cylindricalshape with the bottom, i.e. end, open to the right in FIG. 3, isattached to the input shaft 22 so as to be non-rotatable with respectthereto, as well as so as not to be able to move in the axial direction(i.e., in the direction of the axis 0) (i.e., in the left and rightdirections in the drawing). The piston 38 is fitted inside the cylindertube 36 so as to be able to move along the axis 0. Hydraulic fluid issupplied from a hydraulic fluid passage 41 into a pressure chamber 40between the cylinder tube 36 and the piston 38 so that the piston 38 isforced out in a first direction, i.e., to the right in the drawing,thereby frictionally engaging the first clutch C1. Seal members 42 and44, made of rubber or the like, are fixed to the inner and outerperipheral portions of the piston 38 to seal the pressure chamber 40.Also, a cylindrical connecting drum 46 is integrally attached to a sidewall portion (the outer cylinder portion of the outer peripheral side,in this exemplary embodiment) of the cylinder tube 36 which isintegrally attached to the input shaft 22. This connecting drum 46 iscentered around the axis 0 and extends out in the first direction. Thefirst clutch C1 includes multiple friction members 48 which are attachedto the inner peripheral side of the connecting drum 46 so as to benon-rotatable with respect thereto, and multiple friction members 50which are attached to the second rotating element RM2 so as to benon-rotatable with respect thereto alternately between the multiplefriction members 48. The piston 38 frictionally engages the frictionmembers 48 and friction members 50, thereby connecting the secondrotating element RM2 to the input shaft 22.

The second hydraulic cylinder 34 is provided adjacent, in the firstdirection (i.e., to the right in FIG. 3), to the first hydrauliccylinder 32. The second hydraulic cylinder 34 includes a cylinder tube56 and a piston 58. The cylinder tube 56 is cylindrical with a bottom,i.e. end, that opens to the right in FIG. 3. This cylinder tube 56 ismounted to the input shaft 22 so as to be non-rotatable with respectthereto, and so as not to be able to move in the axial direction (i.e.,the direction of the axis 0). The piston 58 is fitted inside thiscylinder tube 56 so as to be movable in the axial direction. Hydraulicfluid is supplied from a hydraulic fluid passage 61 into a pressurechamber 60 between a cylinder tube 56 and the piston 58 so that thepiston 58 is forced out in the first direction, i.e., to the right inthe drawing, thereby frictionally engaging the second clutch C2. Sealmembers 62 and 64, made of rubber or the like, are fixed to the innerand outer peripheral portions of the piston 58 to seal the pressurechamber 60. Also, the second clutch C2 is mounted to the innerperipheral side of the connecting drum 46 in a location in the firstdirection from the second hydraulic cylinder 34, i.e., further to theright in the drawing than the second hydraulic cylinder 34, so that itis between the second hydraulic cylinder 34 and the first clutch C1 andadjacent to the first clutch C1. The second clutch C2 includes multiplefriction members 68 which are attached to the inner peripheral side ofthe connecting drum 46 so as to be non-rotatable with respect thereto,and multiple friction members 70 which are attached to the fourthrotating element RM4 so as to be non-rotatable with respect theretoalternately between the multiple friction members 68. The piston 58frictionally engages the friction members 68 and friction members 70,thereby connecting the fourth rotating element RM4 to the input shaft22.

The friction members 48 and friction members 50 of the first clutch C1and the friction members 68 and friction members 70 of the second clutchC2 are inserted into the connecting drum 46 from the end portion thereofon the first direction side, from the direction opposite the firstdirection, i.e., inserted to the left in the drawing. The frictionmembers 48 of the first clutch C1 and the friction members 68 of thesecond clutch C2 engage by spline engagement or the like with theconnecting drum 46. Likewise, the friction members 50 of the firstclutch C1 and the friction members 70 of the second clutch C2 engage byspline engagement or the like with the second rotating element RM2 andthe fourth rotating element RM4, respectively. Furthermore, the frictionmembers 68 are prevented from moving in the first direction from thesecond clutch C2 side by a snap ring 52 integrally attached to an endportion of the connecting drum 46, via a spacer 72 that is spline fittedto the connecting drum 46 so as to be non-rotatable with respectthereto. The friction members 68 pressed together between a pressureplate 74, which is held in position by the spacer 72, and the piston 58.Notches 68 a are provided in four locations equal distances apart in thefriction members 68, as shown in FIG. 4, while four engaging prongs 38 aare provided on the piston 38 of the first hydraulic cylinder 32 whichextend in the first direction from the piston 38 in locationscorresponding to the notches 68 a in the friction members 68. Theseengaging prongs 38 a extend through the notches 68 a all the way to thefirst clutch C1. Further, the friction members 48 on the connecting drum46 side of the first clutch C1 are spline fitted to the spacer 72 so asto be non-rotatable with respect thereto. The friction members 48 areprevented from moving in the first direction by the snap ring 52 whichholds the spacer 72 in position. Accordingly, the friction members 48are pressed against the friction members 50 between the pressure plate54, which is held in position by the snap ring 52, and the piston 38.According to this exemplary embodiment, the second clutch C2 mounted onthe side opposite the first direction side in the direction along theaxis 0, i.e., on the left side in FIG. 3, is the one friction engagingdevice, the first clutch C1 is the other friction engaging device, andthe snap ring 52 functions as the stopper member.

FIG. 5A is a cross-sectional view showing in detail how the frictionmembers 68 are engaged with the connecting drum 46 in the second clutchC2. The connecting drum 46 is formed by drawing or bending with a pressinto a wavy shape in which the dimension of the diameter changescyclically around the periphery, and the resultant waves on the innerperipheral surface are used as splines. These splines then mesh with thesplines formed on the outer peripheral portions of the friction members68 so that the connecting drum 46 and the friction members 68 are notable to rotate with respect to one another. Also, FIG. 5B is across-sectional view showing in detail how the connecting drum 46, thespacer 72, and the friction members 48 in the first clutch C1 areengaged with each other. The spacer 72 is formed by drawing or bendingwith a press in a similar fashion into a wavy shape in which thedimension of the diameter changes cyclically around the periphery, andthe resultant waves on the inner and outer peripheral surfaces are usedas splines. These splines then mesh with the waves or splines formed onthe outer peripheral portion of the connecting drum 46, as well as withthe splines formed on the outer peripheral portions of the frictionmembers 48 so that the spacer 72 is non-rotatable with respect to boththe connecting drum 46 and the friction members 48. By using the wavesable to be formed by drawing or bending with a press as splines in thisway, the connecting drum 46 and the spacer 72 can be constructed botheasily and inexpensively.

Referring back now to FIG. 3, the second hydraulic cylinder 34 also hasa cancel plate 80 provided integrally with the input shaft 22. Acentrifugal hydraulic pressure canceling chamber 82 is formed betweenthis cancel plate 80 and the piston 58. The centrifugal hydraulicpressure canceling chamber 82 is on the opposite side of the piston 58from the pressure chamber 60. When hydraulic fluid is introduced intothe centrifugal hydraulic pressure canceling chamber 82 from a hydraulicfluid passage 83, centrifugal hydraulic pressure generated within thepressure chamber 60 as it rotates around the axis 0 is cancelled out.The piston 58 is provided with a cylindrical outer cylinder portion 84.A seal member 86, which is made of rubber or the like, is fixed to theouter peripheral edge of the cancel plate 80 and slides against theinner peripheral surface of the outer cylinder portion 84. This sealmember 86 allows movement by the piston 58 while providing a sealbetween the inner peripheral surface of the outer cylinder portion 84and the cancel plate 80. Inside the centrifugal hydraulic pressurecanceling chamber 82 is a return spring 88 which returns the piston 58to the left in FIG. 3 as the hydraulic pressure within the pressurechamber 60 drops, thereby releasing the second clutch C2.

Also, the first hydraulic cylinder 32 uses the cylinder tube 56 of thesecond hydraulic cylinder 34 as a cancel plate. A centrifugal hydraulicpressure canceling chamber 90 is formed between the cylinder tube 56 andthe piston 38. The centrifugal hydraulic pressure canceling chamber 90is on the opposite side of the piston 38 from pressure chamber 40. Whenhydraulic fluid is introduced into the centrifugal hydraulic pressurecanceling chamber 90 from a hydraulic fluid passage 91, centrifugalhydraulic pressure generated within the pressure chamber 40 as itrotates around the axis 0 is cancelled out. The piston 38 is providedwith a cylindrical outer cylinder portion 92 fitted to the outerperipheral side of the cylinder tube 56. A seal member 94, which is madeof rubber or the like, is fixed to the outer peripheral edge of thecylinder tube 56 and slides against the inner peripheral surface of theouter cylinder portion 92. This seal member 94 allows movement by thepiston 38 while providing a seal between the inner peripheral surface ofthe outer cylinder portion 92 and the cylinder tube 56. Inside thecentrifugal hydraulic pressure canceling chamber 90 is a return spring96 which returns the piston 38 to the left in FIG. 3 as the hydraulicpressure within the pressure chamber 40 drops, thereby releasing thefirst clutch C1.

According to this exemplary embodiment, the cylinder tube 36 and thepiston 38 of the first hydraulic cylinder 32 and the cylinder tube 56,the piston 58, and the cancel plate 80 of the second hydraulic cylinder34 are all made of metal sheeting by drawing with a press.Alternatively, however, they may be cast, die-cast, or forged or thelike, and made of aluminum or an aluminum alloy or the like.

In the dual connecting and disconnecting apparatus 30 according to thisexemplary embodiment, the cylinder tube 56 of the second hydrauliccylinder 34 is provided separate from the piston 38 of the firsthydraulic cylinder 32 and integrally fixed to the input shaft 22, whilethe friction members 48 and friction members 50 of the first clutch C1and the friction members 68 and friction members 70 of the second clutchC2 are all prevented from moving in the first direction by the snap ring52 attached to the connecting drum 46. As a result, when frictionmembers 48 and friction members 50 of the first clutch C1 are pressedtogether by the piston 38, they frictionally engage with each other.Likewise, when the friction members 68 and the friction members 70 arepressed together by the piston 58, they also frictionally engaging witheach other. Therefore, the first hydraulic cylinder 32 and the secondhydraulic cylinder 34 engage and disengage the first clutch C1 and thesecond clutch C2 separately. As a result, it is possible to finelycontrol the engagement torque of the first clutch C1 and the engagementtorque of the second clutch C2 at the same time with a high degree ofaccuracy, thereby improving the degree of freedom of the modes in whichthe first clutch C1 and second clutch C2 can be used.

Also, the friction members 68 on the connecting drum 46 side of thesecond clutch C2 which is arranged adjacent to the second hydrauliccylinder 34 are spline fitted directly to the connecting drum 46 so asto be non-rotatable with respect thereto. The piston 38 of the firsthydraulic cylinder 32 engages the first clutch C1, which is positionedon the first direction side of the second clutch C2 in the axialdirection (i.e., in the direction of the axis 0). The piston 38 of thefirst hydraulic cylinder 32 extends through the notches 68 a in thefriction members 68 and presses against the friction members 48 andfriction members 50 of the first clutch C1. Therefore, there is no needto provide a cylindrical drum and spline teeth or the like on the piston38, as there is when fitting the friction members 68 of the secondclutch C2 to the piston 38 of the first hydraulic cylinder 32 so thatthey are non-rotatable with respect thereto, as is done conventionally.As a result, the shape of the piston 38 is simplified, making the entireapparatus easier and inexpensive to make. Furthermore, there is no fearthat the operating resistance of the piston 38 of the first hydrauliccylinder 32 will change depending on whether or not the second clutch C2is engaged or disengaged so transitional control and the like of theengaging torque during engagement and disengagement of the first clutchC1 is able to be performed with a high degree of accuracy regardless ofwhether the second clutch C2 is engaged or disengaged.

Also, by using the snap ring 52 via the spacer 72 to prevent thefriction members 68 and friction members 70 of the second clutch C2 frommoving in the first direction, the length dimension in the axialdirection (i.e., in the direction of the axis 0) is able to be decreasedcompared to when a snap ring is used to hold the friction members 68 andfriction members 70 of the second clutch C2 in position in the samemanner as on the first clutch C1 side. Also, because the snap ring mustbe compressed in the radial direction when it is fit into an annulargroove for assembly in the connecting drum 46, it is necessary toincrease the radial dimension of the snap ring so that it is greaterthan the radial dimension necessary for engagement with the pressureplate 74, but only by the amount that the snap ring is compressed (i.e.,by only the amount of the snap ring that will fit into the annulargroove in the connecting drum 46) in order to avoid interference withthe engaging prongs 38 a of the piston 38 of the first hydrauliccylinder 32. When the spacer 72 is used, however, its radial dimensiononly needs to be equal to the dimension required to engage the pressureplate 74 and no greater, so the radial dimension of the spacer 72 can bedecreased compared to the radial dimension of the snap ring.

Next, a second exemplary embodiment according to the invention will bedescribed. In the following second exemplary embodiment, members thatare substantially the same as those of the first exemplary embodimentwill be denoted with the same reference numerals and characters, anddescriptions thereof will be omitted.

In the first exemplary embodiment, the cylindrical spacer 72 is usedwhich abuts against the outer peripheral portion of the pressure plate74. Alternatively, however, the end of the spacer 72 may be formed in aflange 102 which is substantially parallel with the pressure plate 74,as shown in a dual connecting and disconnecting apparatus 100 in FIG. 6.In this case, because the pressure plate 74 is supported over a widearea by the flange 102, pressure from the piston 58 is distributedevenly over a wide area of the friction members 68 and friction members70. As a result, localized heat generation and uneven friction areinhibited, and performance in terms of durability and engaging force andthe like of the second clutch C2 is improved. Furthermore, the pressureplate 74 can be made thinner or even eliminated entirely, therebyreducing the cost and enabling the overall length to be reduced. Also,by providing the flange 102, the rigidity of the spacer 72 itself isincreased so the work of pressing it into a wavy shape in which thewaves serve as splines, and the like, is made easier, thereby enablingmanufacturing costs to be reduced.

Notches are provided in the flange 102 just as with the friction members68, so that the engaging prongs 38 a of the piston 38 are able to extendthrough it. Also, in the dual connecting and disconnecting apparatus100, wavy shaped meshing teeth 104 are provided on the engaging prongs38 a portions of the piston 38, which engage with the splines (i.e.,waves) on the connecting drum 46 so that the engaging prongs 38 a of thepiston 38 are non-rotatable with respect the connecting drum 46. Thepiston 38 may be cast, die-cast, or forged or the like, and made ofaluminum or an aluminum alloy or the like, for example. Furthermore,similar meshing teeth may also be provided in the first embodiment.

In comparison with the dual connecting and disconnecting apparatus 100shown in FIG. 6, a dual connecting and disconnecting apparatus 110according to a third exemplary embodiment shown in FIG. 7 is constructedsuch that the radial dimension of the portion of the connecting drum 46where the spacer 72 is fitted, i.e., the radial dimension of the portionon the first direction side, which is the open side (i.e., to the rightin FIG. 7), is relatively larger than the radial dimension of theportion of the connecting drum 46 where the friction members 68 of thesecond clutch C2 are fitted, and the spacer 72 is abutted against a step112 between the two portions of different diameters while allowing thefriction members 68 to be fitted. As a result, the spacer 72 isprevented from moving in the direction opposite the first direction,with the spacer 72 being held in position between the step 112 and thesnap ring 52. This step 112 corresponds to an abutting portion providedintegrally with the connecting drum 46.

In this case, because the spacer 72 is held in position in the axialdirection between the step 112 and the snap ring 52, it is possible toprevent a deterioration in power transmission efficiency and fuelefficiency caused by the spacer 72 moving in the direction opposite thefirst direction when the second clutch C2 is disengaged and causing thefriction members 68 and friction members 70 to slip engage, resulting indragging loss and heat buildup which can burn the friction members 68and friction members 70.

Although exemplary embodiments have been described herein with referenceto the drawings, many modifications and variations therein will readilyoccur to those skilled in the art. Accordingly, all such variations andmodifications are included within the intended scope of the invention.

The cylinder tube 56 of the second hydraulic cylinder 34 is providedseparate from a piston 38 of the first hydraulic cylinder 32 andintegrally fixed to the input shaft 22. Friction members 48 and 50 ofthe first clutch C1 and friction members 48 and 50 of the second clutchC2 are prevented from moving in a first direction by the snap ring 52attached to the connecting drum 46. The friction members 48 and 50 ofthe first clutch C1 are friction engaged by the piston 38 and thefriction members 48 and 50 of the second clutch C2 are friction engagedby the piston 58.

1. A dual connecting and disconnecting apparatus comprising: a firsthydraulic cylinder in which a piston is moved in a first direction whichis parallel with an axis of the dual connecting and disconnectingapparatus by supplying hydraulic fluid into a first pressure chamber; asecond hydraulic cylinder which is integrally provided on a commonsupport member and which is concentric with the first hydraulic cylinderin a position adjacent in the first direction to the first hydrauliccylinder, and in which a piston is moved in the first direction bysupplying hydraulic fluid into a second pressure chamber; a cylindricalconnecting drum provided on a side wall portion of a cylinder tube ofthe first hydraulic cylinder integrally mounted to the support member,the connecting drum being centered around the axis and extending out inthe first direction; a first friction engaging device positioned fartherto the first direction side than the second hydraulic cylinder, thefirst friction engaging device comprising (i) a first friction memberprovided on the connecting drum, this connecting drum being rotatablearound the axis with respect to a first connecting member, the firstfriction member being non-rotatable with respect to the connecting drum,and (ii) a second friction member provided on the first connectingmember, the second friction member being non-rotatable with respect tothe first connecting member, the first friction engaging deviceconnecting the support member with the first connecting member via theconnecting drum by moving the piston of the first hydraulic cylinder inthe first direction and engaging the first friction member of theconnecting drum with the second friction member of the first connectingmember; and a second friction engaging device positioned farther to thefirst direction side than the second hydraulic cylinder and adjacent inthe axial direction to the first friction engaging device, the secondfriction engaging device comprising (i) a third friction member providedon the connecting drum, this connecting drum being rotatable around theaxis with respect to a second connecting member, the third frictionmember being non-rotatable with respect to the connecting drum, and (ii)a fourth friction member provided on the second connecting member, thefourth friction member being non-rotatable with respect to the secondconnecting member, the second friction engaging device connecting thesupport member with the second connecting member via the connecting drumby moving the piston of the second hydraulic cylinder in the firstdirection and engaging the third friction member of the connecting drumwith the fourth friction member of the second connecting member, acylinder tube of the second hydraulic cylinder is provided separatelyfrom the piston of the first hydraulic cylinder, and is fixed integrallyto the support member, and the first friction member and the secondfriction member of the first friction engaging device and the thirdfriction member and the fourth friction member of the second frictionengaging device are fitted into the connecting drum from an end portionthereof on the first direction side from the direction opposite thefirst direction, and are prevented from moving in the first direction bya stopper member integrally attached to the connecting drum, whereinamong the first friction engaging device and the second frictionengaging device, the friction member of the one friction engaging devicearranged on the side opposite the first direction side in the axialdirection is prevented from the first direction side, from moving in thefirst direction by a spacer fitted to the connecting drum so as to benon-rotatable with respect thereto; and the friction member on theconnecting drum side of the other friction engaging device positioned onthe first direction side is fitted to the spacer so as to benon-rotatable with respect thereto, and is prevented, along with thespacer, from moving in the first direction by the stopper member.
 2. Thedual connecting and disconnecting apparatus according to claim 1,wherein: among the first friction engaging device and the secondfriction engaging device, the friction member on the connecting drumside of the one friction engaging device arranged on the side oppositethe first direction side in the axial direction is mounted to theconnecting drum so as to be non-rotatable with respect thereto; and thepiston of the hydraulic cylinder that engages the friction member of theother friction engaging device positioned on the first direction sideextends through a notch formed in the friction member of the onefriction engaging device and abuts against the friction member of theother friction engaging device.
 3. The dual connecting and disconnectingapparatus according to claim 1, wherein: the first friction member andthe second friction member are pressed together between the piston ofthe first hydraulic cylinder and the stopper member and engaged bymoving the piston in the first direction; and the third friction memberand the fourth friction member are pressed together between the pistonof the second hydraulic cylinder and the stopper member via the spacerand engaged by moving the piston in the first direction.
 4. The dualconnecting and disconnecting apparatus according to claim 1, wherein: anannular flange bent at a substantially right angle away from theconnecting drum so as to be substantially parallel with the frictionmember of the one friction engaging device is integrally provided on anend of the spacer.
 5. The dual connecting and disconnecting apparatusaccording to claim 1, wherein: the spacer is prevented from moving inthe direction opposite the first direction by an abutting portionprovided integrally with the connecting drum so as to allow fitting ofthe friction member of the one friction engaging device, and is held inposition between the abutting portion and the stopper member.
 6. Thedual connecting and disconnecting apparatus according to claim 1,wherein: the support member is a rotating input shaft of the dualconnecting and disconnecting apparatus.
 7. The dual connecting anddisconnecting apparatus according to claim 1, wherein: the firstfriction member and the second friction member of the first frictionengaging device are provided in plurality; and the third friction memberand the fourth friction member of the second friction engaging deviceare provided in plurality.